[openvrml-develop] Re: Problems with normal vectors beeing not normalized

[<MSo...@ya...>]

Hi Braden,

> > The normals are not smoothed (the face is rendered with 
> flat color as 
> > it should be) but the normal vector is not normalized.
> 
> "Not normalized"? I don't know what you mean by that. "Not
normalized"
> generally means that the components haven't been adjusted to 
> be proportional to 1. But the case here is that OpenVRML 
> isn't supplying OpenGL with normals because it hasn't generated
them.

OpenVRML creates the right normal vectors in this case. The only
problem with these normal vectors is, that their length is not 1, as
it should be for a normal vector. Most shaders go wild if you supply
unnormalized normal vectors. If I tell OpenGL to normalize all normal
vectors (that is to keep their directions but to devide them by their
length) the model looks perfect. But normalizing all normal vectors is
a time consuming operations, because it requires calculating a square
root and a division for every normal vector. Since 99.99% of all
normal vectors already have a length of 1, this would be quite a waste
of computation time.

Best regards,

Michael

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